Thank you very much Jeff,
I moved ipm_Lisen after received event IPMEV_GET_XMITTS_INFO and now imp_listen success. But unfortunately when A talk, B don't hear anything, B talk A don't hear anything also :( . This is log
[2015-12-02 09:15:57] Received IPMEV_GET_XMITTS_INFO for device = ipmB1C2
[2015-12-02 09:15:57] Timeslot number 4647
[2015-12-02 09:15:57] ipm_Listen success ipmB1C3
[2015-12-02 09:15:57] Received a non-GC Event 0x9008
[2015-12-02 09:15:57] IPMEV_GET_XMITTS_INFO
[2015-12-02 09:15:57] Received IPMEV_GET_XMITTS_INFO for device = ipmB1C3
[2015-12-02 09:15:57] Timeslot number 4648
[2015-12-02 09:15:57] ipm_Listen success ipmB1C2